Some examples of nitrates are nitroglycerin Nitro-Dur, Nitrostat, others , isosorbide mononitrate Monoket and isosorbide dinitrate Bidil. Do not take vardenafil more than once a day. This medicine works best when you take it on an empty stomach an hour before sex. They enhance the effects of a chemical the body makes that relaxes muscles in the penis, called nitric oxide. These include itraconazole Sporanox, Tolsura , ketoconazole Extina, Ketozole, others and ritonavir Norvir. Grapefruit and Seville oranges may interact with vardenafil and cause side effects.Generic Levitra Availability. Last updated on Levitra is a brand name of vardenafil, approved by the FDA in the following formulation(s): provides accurate and independent information on more than 24, prescription drugs, over-the-counter medicines and natural products. This material is . If you do buy medicines over the internet: Check to see if an online pharmacy is legitimate. Never order medicines from an online pharmacy that doesn’t . Extra 15% off $30 sitewide with code SAVE15; Clip your mystery deal! BOGO 50% off select Walgreens health & wellnessMissing: levitra.